Signals

Additional Inherited Members

Detailed Description

The QDataWidgetMapper class provides mapping between a section of a data model to widgets.

QDataWidgetMapper can be used to create data-aware widgets by mapping them to sections of an item model. A section is a column of a model if the orientation is horizontal (the default), otherwise a row.

Every time the current index changes, each widget is updated with data from the model via the property specified when its mapping was made. If the user edits the contents of a widget, the changes are read using the same property and written back to the model. By default, each widget's user property is used to transfer data between the model and the widget. Since Qt 4.3, an additional addMapping() function enables a named property to be used instead of the default user property.

It is possible to set an item delegate to support custom widgets. By default, a QItemDelegate is used to synchronize the model with the widgets.

Let us assume that we have an item model named model with the following contents:

1

Qt Norway

Oslo

2

Qt Australia

Brisbane

3

Qt USA

Palo Alto

4

Qt China

Beijing

5

Qt Germany

Berlin

The following code will map the columns of the model to widgets called mySpinBox, myLineEdit and myCountryChooser:

After the call to toFirst(), mySpinBox displays the value 1, myLineEdit displays Qt Norway and myCountryChooser displays Oslo. The navigational functions toFirst(), toNext(), toPrevious(), toLast() and setCurrentIndex() can be used to navigate in the model and update the widgets with contents from the model.

The setRootIndex() function enables a particular item in a model to be specified as the root index - children of this item will be mapped to the relevant widgets in the user interface.

QDataWidgetMapper supports two submit policies, AutoSubmit and ManualSubmit. AutoSubmit will update the model as soon as the current widget loses focus, ManualSubmit will not update the model unless submit() is called. ManualSubmit is useful when displaying a dialog that lets the user cancel all modifications. Also, other views that display the model won't update until the user finishes all their modifications and submits.

Note that QDataWidgetMapper keeps track of external modifications. If the contents of the model are updated in another module of the application, the widgets are updated as well.

If the orientation is Qt::Horizontal (the default), a widget is mapped to a column of a data model. The widget will be populated with the model's data from its mapped column and the row that currentIndex() points at.

If the orientation is set to Qt::Vertical, a widget is mapped to a row. Calling setCurrentIndex() will change the current column. The widget will be populates with the model's data from its mapped row and the column that currentIndex() points at.

QDataWidgetMapper::~QDataWidgetMapper ()

Adds a mapping between a widget and a section from the model. The section is a column in the model if the orientation is horizontal (the default), otherwise a row.

For the following example, we assume a model myModel that has two columns: the first one contains the names of people in a group, and the second column contains their ages. The first column is mapped to the QLineEditnameLineEdit, and the second is mapped to the QSpinBoxageSpinBox:

Warning: You should not share the same instance of a delegate between widget mappers or views. Doing so can cause incorrect or unintuitive editing behavior since each view connected to a given delegate may receive the closeEditor() signal, and attempt to access, modify or close an editor that has already been closed.